Zeaxanthin is contained in various plants such as corn, added to feed as natural yellow pigment, and known to have applications for improving the color tone of egg yolk, meat, or skin of a fowl such as chicken and uses as a coloring agent for food. It also has a potent antioxidant effect (Fisheries Science, 62(1): 134-137, 1996), and has been reported to have an anti-tumor effect (Biol. Pharm. Bull., 18(2): 227-233, 1995). Zeaxanthin is known to be, together with lutein, present in the retina and lens and involved in the maintenance of eye health (FOOD Style 21, 3(3): 50-53, 1999). Due to these physiological effects, zeaxanthin is useful as a health food, cosmetic, or pharmaceutical material. β-Cryptoxanthin is contained in citrus fruits, known to have an anti-tumor effect (Biol. Pharm. Bull., 18(2): 227-233, 1995), and has applications as a food material or a compounding ingredient for feed. β-Carotene has provitamin A and antioxidant actions and is widely used as feed additive, food additive, natural coloring agent, or the like.
Known as a process for producing zeaxanthin are chemical synthesis using, as a raw material, an optically active hydroxyketone obtained by the asymmetric reduction of oxoisophorone (Pure Appl. Chem., 63(1): 45, 1991) and extraction from corn seeds (Seitai Shikiso (Biochrome), 1974, Asakura-shoten). A process by extraction from marigold is also known (JP Patent Publication (Kokai) No. 08-092205 A (1996)); however, a marigold-derived carotenoid mainly comprises lutein and has a reduced content of zeaxanthin. Further, microorganisms for production thereof include Spirulina algae (JP Patent Publication (Kokai) No. 10-155430 A (1998)), Nannochloris spp. microalgae (JP Patent Publication (Kokai) No. 07-059558 A (1995)), Flexibacter spp. bacteria (JP Patent Publication (Kokai) No. 05-328978 A (1993)), Alteromonas spp. bacteria (JP Patent Publication (Kokai) No. 05-049497 A (1993)), Flavobacterium spp. bacteria (Carotenoids, in Microbial Technology, 2nd edn, Vol. 1, 529-544, New York: Academic Press), Agrobacterium aurantiacum (FEMS Microbiology Letters, 128: 139-144, 1995), and a bacterial strain, E-396 (FERM BP-4283) belonging to a novel genus (JP Patent Publication (Kokai) No. 07-079796 A (1995), JP Patent Publication (Kokai) No. 08-009964 A (1996), U.S. Pat. No. 5,607,839, and U.S. Pat. No. 5,858,761).
β-Carotene is a natural yellow carotenoid contained in green and yellow vegetables such as carrot and finds wide use as a coloring agent for foods such as batter and margarine. It also has provitamin A activity and is an important nutrient for human. This substance is known to have an antioxidant effect (Fisheries Science, 62(1): 134-137, 1996) and has been reported to have anti-tumor and anti-cancer effects (Biol. Pharm. Bull., 18(2): 227-233, 1995). Due to these physiological effects, β-carotene is useful not only as a coloring agent, but also as a functional material for use in feed, food, cosmetics, or pharmaceuticals.
Known as a process for producing β-carotene are chemical synthesis from β-ionone (Pure Appl. Chem., 63(1): 45, 1979) and extraction from green and yellow vegetables such as carrot, sweetpotato, and pumpkin (Tennen Chakusyokuryo (Natural Coloring Agents) Handbook, Korin Publishing Co., Ltd., Tennen Chakusyokuryo Handbook Editorial board ed.). In addition, as example of production of β-carotene by a microorganism is known that by Dunaliella algae (J. Phycol, 23: 176, 1987), Blakeslea trispora (filamentous fungi) (Appl. Environ. MicroBiol. 36: 639-642, 1979), Phaffia rhodozyma (yeast) (JP Patent Publication (Kokai) No. 05-168465 A (1993)), Rhodotorula spp. yeasts (JP Patent Publication (Kokai) No. 06-022748 A (1994)), Agrobacterium aurantiacum (FEMS Microbiology Letters, 128: 139-144, 1995), or the bacterial E-396 strain (FERM BP-4283) belonging to a novel genus (JP Patent Publication (Kokai) No. 07-079796 A (1995), JP Patent Publication (Kokai) No. 08-009964 A (1996), U.S. Pat. No. 5,607,839, and U.S. Pat. No. 5,858,761).
Lycopene is a natural red carotenoid contained in tomato and useful as a coloring agent for food. It also has a potent antioxidant effect (Arch. Biochem. Biophys., 271: 532, 1989), is known to inhibit the oxidation of low density lipoproteins associated with arteriosclerosis (Nutr. Metab. Cordiovasc. Dis 7: 433, 1997) and has been reported to suppress the proliferation of cancer cells (J. Natl. Cancer Inst. 91: 313, 1999). Due to these physiological effects, lycopene is useful as a material for use in feed, food, cosmetics, or pharmaceuticals.
Known as a process for producing lycopene are chemical synthesis using linalool or geraniol as raw material (JP Patent Publication (Kokai) No. 2001-039943 A (2001)) and separation and refinement from tomato (JP Patent Publication (Kokai) No. 2002-193850 A (2002)). In addition, microorganisms for production of lycopene include Dunaliella algae (JP Patent Publication (Kokai) No. 2001-161391 A (2001)), Chlorella algae (JP Patent Publication (Kokai) No. 2000-152778 A (2000)), and Rhodobacter spp. bacteria (JP Patent Publication (Kokai) No. 08-239658 A (1996)). The bacterial E-396 (FERM BP-4283) strain belonging to a novel genus (JP Patent Publication (Kokai) No. 07-079796 A (1995), JP Patent Publication (Kokai) No. 08-009964 A (1996), U.S. Pat. Nos. 5,607,839, and 5,858,761) is also known to produce carotenoid compounds at high concentrations, but the level of lycopene production is minimal.
However, the above-described processes for chemically synthesizing zeaxanthin, β-carotene, and lycopene have problems in terms of safety and the directional trend of recent years toward a natural product because their use of organic solvents. Also, the conventional cultivation using a microorganism is not practical because of low productivity, and extraction from a plant (for example, corn, carrot, tomato, or the like) has the disadvantages of requiring too much cost because of its low content of a desired carotenoid compound and making its stable supply difficult because of weather dependency. The E-396 strain, which is known as a microorganism producing carotenoid compounds, has low product proportions of zeaxanthin, β-carotene, and lycopene to the total carotenoids, although it has provided an established process for producing, at high concentrations on an industrial scale, carotenoid compounds having safety already confirmed by various tests and including astaxanthin.
Thus, there is need for an inexpensive process for producing zeaxanthin, β-carotene, and lycopene with high safety, by which they can be stably supplied.